Isomerization of aromatic compounds



Patented Nov. 11, 1952 UNITED STATES-2 PATENT? I MPOU'NDS Joseph E. Nickels, Pittsburgh, Pa., asfsighonto Koppers Company, Inc., Pittsburgh, Pa acorporation of Delaware NoDrawingg Applicationtoetober 2, 1947,;

Serial" N 0. 77 7,581

naphthalenem-ay} be-aefiectedover various alumi-s numgicatailysts'g asawe-ll as: other catalystsrsuchi; as etatphosphateri Itdsrthus possiblezto-o'cone duct a wide' rvariety of: :vapor, f PhaSGJ-CiSOmBIiZHE -T ti'ons.myolving;positionjisomersiof:aromatic com pounds.

Lam taware als'o thatgslike? isomeriz'ations. have befinetefifldtedtin the prior kart tusing-gaaFriedeli- Grafts, atailyst andtcthatz:imsuch processes 'it' is common a use :hydrogemchloride. as; apromoter. The: ctiongof hydrog en ,-/oh1oride;in-suchi' cases is due apparently tothe'v gizeaten solubility which it imparts to the/EriedeleCrafts; catalysts; e 9., 3,1111 minum -i ohlorideqiny the- -hydrocarbon. The; proc:-- esses to which,the presentjinventionre1ates, how eV eI,ga1Y&-' oitan :entirely vdifferent type from. the Eniedel-Grafts processes, that; they-involve" vapoltsphase catalysis in whichwa-pors of:-theiproisomate i.- ,e.-' the materialisubiected to is'omeri-a zations arer ntacted with a1solidcatalytic-mate-r 'oregenerally ofithe surface active-twee I In arming out; theemfo'cesseseof the latter type;

' to saw; processes td-whichthis; invention. the;;catalyst;tendsa=torbecomeinactivated b yythekdeposition of canbon or duetoother causes. Similarly, the activity:;of'v a: regenerated catalystmay-Joe;10wandefortthat matter even the activity oiflanewly. formed catalyst may be--too-1ow. Thereisjthe needlinvtheart; :thereforaior asimple way ti i atinesuch catalysts.

M I have nowjound thatiin. vaponiphasevi omere 1-3 Gl'aims.-r (019260-4668) I 2v ization processes of the charactei aboye desbrified the catalystfmayhe aetivate'd'"by moor-powwow hydrogen halide -int'o =the vapors' of- 'the proisoa In carrying out' suitable amount of hydrogen halide ei-ther ass'uoh or inthe-Torm of-a compouhd 'which} under"the conditions of the' i'somerizatiim'; breaks-flown to give hydrogen halide; ln othenwords, the hydrogen halide may be added as such 01 formed .in situ'-- from -"a'- suitable -h'ydrogen halide? precursor added tothe' gas stream: The mixture "is "then. passed over the so1id'cata1ysta't. a temperature and pressure charac'teristic "of-the"isomerization as determined bythe'nature=of' the proiso'rnate and 'the'catalyst; l a p The invention-*-maybe" more fully understood by reference-to the followingy'examples"hi which the parts-are by weightand'in the 1 c: i g: s; s'y's tent-unless otherwise specified:

A1;mixturesconsisting essentially of =eth'ylnaph thale'nesi: and? analyzing :3;5 polyethylna-phthw lenes and 96.5% ethylnaphthalenes of which 50.7% was l-ethylnaphthalene-hnd 49.2% was 2- ethylnaphthalene,.v was vaporized and" preheated to 425" C; and'apa'sse'dl through "a -catalyst? bed heated to 425 C.'. The. catalyst; waswaeregen precipitation of magnesiu'm andaluminum: ch10 ride hyga'dditionofammonia, The regeneration was effected fby} heating; the spentcatalystzat about"550 C'." in astream of air-. for ahoutgi passed .throughthe' catalyst hed -Iat a..1'ate-- of 0.5 volume of liquid per. VOmmelOfQ catalyst pet;v hour:

that is'to say; at" a liquid hom ly spacewvelocity- (L. H. S. V.) of 0. and the'run was continued for 42 hours. After:18 hours'onstream, hydrogen chloride was ;introduced into"- the 1 preheaterrat the; rate of about 2.5. parts of hydrogen-chloride foizevery 100 parts of-proisomatee This was con"- tinued' for 12 hours with: dryhydrogen chloride and thenifor an additional-.12 hourswith hydrogens-chlorides saturated with. .water byffir'st b'ub iblinga-i it through-:concentrated hydrochloric acid;- The 1averagespigoductsdistributionzonthe"praisemate was: gases 0.0%, liquid 99.8%, and carbon 0.2%. The distribution of isomers in the isomate is given in the following table: The average liquid composition was naphthalene 0.7%, ethylsame rate as in Example I and the temperature was 425 C. Without hydrogen chloride 3.3% l-ethylnaphthalene isomerized, whereas with hydrogen chloride 19.7% isomerized.

naphthalene 97 .4 polyethylnaphthalenes 1.9%. 5 While I have illustrated my invention with ref- Table Time on Stream, hrs -12 12-18 18-24 24-30 case 3642 Hydrogen Chloride none none dry dry moist moist 2-EN in EN Fract., wt. percent 66.2 01.0- 711 78.0 73.0 73.7

Average, wt. percent 64. 75. 5

1-EN lsomerized, wt. percent" 33.4 23.1 54.9 56.7- 46.8 48.2

Average, wt. percent 30.0 51.7

N on: .EN= ethylnaphthalene.

It will be observed that hydrogen chloride" 'erence to particular embodiments thereof. it is caused a substantial increase in the activity of to be understood that variation may be made the catalyst even after the activity of the catatherein without departing from the spirit and lyst had begun to drop off substantially. More- 25 scope of the invention. Thus, variation may be over, the average conversion effected during the made in time, temperature, pressure, proportions, introduction of hydrochloric acid was substancatalysts, proisomate, etc. without departing from tially greater than that during the time when the spirit and scope of the invention. hydrogen chloride was not added. It may be While, in the examples, atmospheric pressure observed still further that the greatest converhas been used, it is to be understood that the sion is obtained with dry hydrogen chloride. It pressure may be either superatmospheric or less is significant to note that after 42 hours the catathan atmospheric. In other words, the pressure lyst was more active than at the beginning clue is not critical and any pressure up to the critical to the actification of the hydrogen chloride. pressure may be used. The temperature, like- EXAMPLE II wise, is illustrative and substantial variation from the 425 C. given in the examples may be made The procedure of EX p e I w duplicated without departing from the spirit and scope of us freshly P pared Mg0 20 Catathe invention. Sincethis invention is in the ly te u was continued r. 24 hours, the nature ofan improvement in isomerization procfirst 12 of which was made without an activator, esses, in which the temperature conditions are a the last 12 withohloroform as e activator. not substantially effected, the temperatures used Thus. during the s 12 hours of e run may be those which are useful in the original parts f chloroform for every 0 pa ts of process. In general, however, a somewhat lower isomate was introduced into the vaporizer. The temperature may be used due to the increased temp a s 5 d t e liquidhoully activity of the catalyst. The temperature may space velocity was 0.50. During the first 12 hours vary somewhat according t the nature of the 0% 0f the l-ethylnaphthaiene isomerized t catalyst and the proisomate, but ordinarily satiscthylnaphthalene as during the second 12 factory results will be obtained within the range ho period 30% is0mc ed, huS d c t g of from 300 C. to 650 C. especially for ethylstantial activation of the catalyst by the chloro- 50 naphtha1enes form. The liquid hourly space velocity may be varied, EXAMPLE III also according to the nature of the proisomate,

The procedure of Example I a followed using temperature of operation and the catalyst or in Silica gel as the catalyst; Two separate runs accordance with the preference of the operator. were made, one with a hydrogen chloride and Generally speaking, however, little advantage is one without. With hydrogen chloride the liquid F m by @Ont? Contact times so that Space hourly space velocity of ethylnaphthalene was iocliles rangmg from to 10 Volumes of P -0.50, without hydrogen chloride it was 0.45. With 9 per v111me P catalyst P hour l hydrogen chloride the length of the run was 15 dummy Produce satisfactory re5u1t$- hours; without, it was 10 hours. In both cases the 0 Vanatwn may a be made in the amount o temperature was 425 C. Without hydrogen chlothe hydrsogen hahde; likewise any of the hydroride 9.3% l-ethylnaphthalene isomerized, wheregen Pahdes may be used in plaooof h d e .as with hydrogen chloride 31.1% isomerized. chlollde; The amount required i very small in Hydrogen chloride was introduced at the same proportlon to the amount of proisomate procrateas in Example L r essed, but the amount may rang to a, s b t tlal portion of the mixture passed'through the v 7 EXAMPLE IV catalyst bed. Quantities greater than about 15 The procedure of'Example I-was followed using Parts for each 100 parts of proisomate, ow iron meta phosphate as the catalyst. Two runs appear to be unnecessary and 110 act y s diluwere made; one with hydrogen chloride and one em? Carrier gas inthe p ocess. without. With hydrogen chloride the liquid Generally p k y one of two or more hourly space velocity of ethylnaphthalene' was position ers may be converted to another, 0.50; without, it was 0.46. With hydrogen chlo- For example, l-ethylnaphthalene may b ride the length of the runwas 15; without, it was verted to Z-ethylnaphthalene and vice v r 10, Hydrogenchlonde was introduced at the With a sufiic'iently activated catalyst it is possible to approach the equilibrium composition from either side. With ethylnaphthalene the equilibrium concentration appears to be in the vicinity of 80% of the 2-isomer and of the l-isomer. With a sufficiently active catalyst this equilibrium mixture can be attained or approached from either side. -Hydrogen halide may be used effectively, even with such highly active catalysts and afiord advantages in lowered temperatures and/ or increased space velocities.

While the invention has been illustrated in the examples with reference to ethylnaphthalenes, it is to be understood that in its broader aspects the invention is applicable to efiecting isomeric rearrangements in other aromatic compounds capable of existing in two or more position isomers,

9. The process of claim 2 in which the hydro- 7 gen halide is hydrogen chloride.

such, for example, as the dialkyl benzenes such as the xylenes, the diethyl benzenes and like benzene derivatives, the alkylated naphthalenes such as methyl and ethyl naphthalene and the higher homologues thereof, alkylated phenols suchas cresols, xylenols, ethyl phenols and higher homologues thereof, dinaphthyls, halogenated benzenes and naphthalenes and like substituted aromatic compounds.

Having thus fully described my invention, what I now claim as new and desire to secure by Letters Patent is:

1. In a process for the catalytic is-omerization of a proisomate consisting essentially of a substituted aromatic compound. capable of existing in the form of two or more position isomers, the steps of vaporizing the proisomate, combining the proisomate vapors with a hydrogen halide and passing the mixture thus obtained over an isomerization catalyst under isomerizing conditions, in which said catalyst is a magnesia-alumina catalyst.

2. The process of claim 1 in which the isomerization is afiected in the absence of moisture,

3. The method of claim 1 in which the hydrogen halide is hydrogen chloride.

4. The process of claim 3 in which the hydrogen chloride is added as such.

5. The process of claim 3 in which the hydrogen halide is generated in situ. I

6. The process of claim 1 in which the proisomate is ethylnaphthalene.

7. The process of claim 6 in which the proisomate contains l-ethylnaphthalene in excess of the equilibrium mixture.

8. The method of claim 6 in which the 1- and 10. The process of claim 9 in which the proisomate is ethyl naphthalene.

11. The process of claim 1 in which the substituted aromatic com-pound is one of the ethylnaphthalene isomers and in which the catalysis is effected by passing the proisomate vapors in admixture with the hydrogen halide in contact with the catalyst at a temperature between 300 C. and 650 C. at a liquid hourly space velocity ranging from 0.2 to 10, and in which the amount of hydrogen halide is not in excess of 15 parts for each parts of proisomate.

12. The process of isomerizing alpha-ethylnaphthalene to beta-ethylnaphthalene in a mixture containing substantially equal parts of the two isomers which comprises vaporizing said mixture, passing the vapors in admixture with hydrogen halide in contact with magnesia-alumina catalyst under isomerizing conditions.

13. The process of claim 12 in which the contact is effected at a temperature between 300- C. and 650 C. at a lquid hourly space velocity ranging from 0.2 to 10, and in which the amount of hydrogen halide is not in excess of 15 parts for each 100 parts of proisomate.

JOSEPH E. NICKELS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS OTHER REFERENCES Eglofi et al.: Isomerization of Pure Hydrocarbons, pub. Reinhold Pub. Corp., New York (1942), pp. 386, 387 (2 pages). 

12. THE PROCESS OF ISOMERIZING ALPHA-ETHYLNAPTHALENE TO BETA-ETHYLNAPTHALENE IN A MIXTURE CONTAINING SUBSTANTIALLY EQUAL PARTS OF THE TWO ISOMERS WHICH COMPRISES VAPORIZING SAID MIXTURE, PASSING THE VAPORS IN ADMIXTURE WITH HYDROGEN HALIDE IN CONTACT WITH MAGNESIA-ALUMINA CATALYST UNDER ISOMERIZING CONDITIONS. 